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Part of the problem may have to do specifically with yahoo mail servers.
As far as I'm concerned, yahoo free-crap accounts are just that ... because my wife and I do a lot of eBaying and the only mails we EVER have problems with are from yahoo users. After doing some goggling ... come to find out that there are thousands of complaints to yahoo starting in the summer of 2006 when yahoo servers began to almost randomly filter spam in a way which prevents yahoo account holders from RECEIVING mail from people who are not yahoo account holders. Regardless if in the USA (where we were) or overseas like in Germany (where we're at now), we've had problems with yahoo mail from both sides of the pond.

Here's one of the more interesting (loooong) reads on the subject:http://www.ahfx.net/weblog.php?article=107

Right at this very moment I know about half a dozen people with yahoo accounts who are not receiving mail from friends and family members that have their email from smaller ISPs etc. Just a little something to think about ...
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